When using , users often encounter the frustrating "Virtual USB Bus Error Code 39." This error prevents the software from recognizing the license key (HASP), rendering the application unusable. Most commonly, this is caused by a security feature in modern Windows versions known as Core Isolation (Memory Integrity) , which blocks older or virtual drivers from loading.
Below is a comprehensive guide to resolving this error for both Windows 10 and 11. Understanding Error Code 39 mastercam x72022 virtual usb bus error 39 updated
Navigate to the following path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity Find the value named . Right-click it, select Modify , and set the Value data to 0 . Restart your PC. 3. Delete Registry "Filters" (For Corrupted Drivers) When using , users often encounter the frustrating
Sometimes the error is caused by invalid "UpperFilters" or "LowerFilters" keys in the Windows registry that block USB drivers from loading. Understanding Error Code 39 Navigate to the following
The most common cause of Error 39 is , specifically the Memory Integrity setting. Turning this off allows the virtual USB bus to load correctly. Open the Start Menu and search for Windows Security . Navigate to Device security on the left sidebar.
Many Mastercam installations use a virtual USB bus (like MultiKey) to manage the HASP/LDK license. Older versions of these virtual drivers are frequently flagged as incompatible by newer Windows updates. Step-by-Step Fixes (Updated for 2024–2025) 1. Disable Core Isolation (Recommended Fix)
If you cannot toggle Core Isolation via the settings menu, you can force it off through the . Press Win + R , type regedit , and press Enter .